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# pylint: disable=missing-function-docstring
"""
This sample "listen to directory". move the new file and print it,
using docker-containers.
The following operators are being used: DockerOperator,
BashOperator & ShortCircuitOperator.
TODO: Review the workflow, change it accordingly to
      your environment & enable the code.
"""

from datetime import timedelta

from docker.types import Mount

from airflow import DAG
from airflow.operators.bash import BashOperator
from airflow.operators.python import ShortCircuitOperator
from airflow.providers.docker.operators.docker import DockerOperator
from airflow.utils.dates import days_ago

default_args = {
    "owner": "airflow",
    "depends_on_past": False,
    "email": ["airflow@example.com"],
    "email_on_failure": False,
    "email_on_retry": False,
    "retries": 1,
    "retry_delay": timedelta(minutes=5),
}

dag = DAG(
    "docker_sample_copy_data",
    default_args=default_args,
    schedule_interval=timedelta(minutes=10),
    start_date=days_ago(2),
)

locate_file_cmd = """
    sleep 10
    find {{params.source_location}} -type f  -printf "%f\n" | head -1
"""

t_view = BashOperator(
    task_id="view_file",
    bash_command=locate_file_cmd,
    do_xcom_push=True,
    params={"source_location": "/your/input_dir/path"},
    dag=dag,
)


def is_data_available(*args, **kwargs):
    """Return True if data exists in XCom table for view_file task, false otherwise."""
    ti = kwargs["ti"]
    data = ti.xcom_pull(key=None, task_ids="view_file")
    return not data == ""


t_is_data_available = ShortCircuitOperator(
    task_id="check_if_data_available", python_callable=is_data_available, dag=dag
)

t_move = DockerOperator(
    api_version="1.19",
    docker_url="tcp://localhost:2375",  # replace it with swarm/docker endpoint
    image="centos:latest",
    network_mode="bridge",
    mounts=[
        Mount(source="/your/host/input_dir/path", target="/your/input_dir/path", type="bind"),
        Mount(source="/your/host/output_dir/path", target="/your/output_dir/path", type="bind"),
    ],
    command=[
        "/bin/bash",
        "-c",
        "/bin/sleep 30; "
        "/bin/mv {{params.source_location}}/{{ ti.xcom_pull('view_file') }} {{params.target_location}};"
        "/bin/echo '{{params.target_location}}/{{ ti.xcom_pull('view_file') }}';",
    ],
    task_id="move_data",
    do_xcom_push=True,
    params={"source_location": "/your/input_dir/path", "target_location": "/your/output_dir/path"},
    dag=dag,
)

print_templated_cmd = """
    cat {{ ti.xcom_pull('move_data') }}
"""

t_print = DockerOperator(
    api_version="1.19",
    docker_url="tcp://localhost:2375",
    image="centos:latest",
    mounts=[Mount(source="/your/host/output_dir/path", target="/your/output_dir/path", type="bind")],
    command=print_templated_cmd,
    task_id="print",
    dag=dag,
)

t_view.set_downstream(t_is_data_available)
t_is_data_available.set_downstream(t_move)
t_move.set_downstream(t_print)
